One of our client wanted to have the credit card tab opened when user proceeds to checkout using PayPal. I had to search for hours doing so. Later i resolved it going through certain documentation of PayPal and searching for codes in Magento API calls for PayPal.
This is what i did. I originally posted the answer in my Stack exchange profile too. The link for it is Adding Credit Card Tab
Please check the image for it
So, what i did was
1) I checked for PayPal’s API Calls from developer profile. The link for it is PayPal API
To open the credit card option by default you need to pass the API with parameters LANDINGPAGE=Billing.
2) Searched for API calls in Magento for PayPal and found the file Nvp.php at app/code/core/Mage/Paypal/Model/Api/Nvp.php
3) Search for the function callSetExpressCheckout() after $this->_exportLineItems($request); enter the following line $request[‘LANDINGPAGE’] = ‘Billing’;
This is it. Now the credit card tab will be opened by default. This method will work only with PayPal Express Checkout and not with PayPal Standard checkout.